We maintain a Critical Process Control Laboratory which is used to closely monitor the cleanliness of high-reliability and mission-critical printed circuit board assemblies used in harsh environment applications. We continuously monitor the presence of anions, cations and weak organic acids as contamination originating from the supply chain as residues from processes and chemistries used in raw material production and upstream through to the printed circuit board assembly process to ensure that it is thoroughly removed in accordance with both internal and customer requirements prior to installation and operation in accordance with the following test methods:

TEST METHOD DESCRIPTION
IPC TM-650 2.3.25 RESISTIVITY OF SOLVENT EXTRACT (ROSE)
IPC TM-650 2.3.25.1 IONIC CLEANLINESS TESTING OF BARE BOARDS
IPC TM-650 2.3.28 IONIC ANALYSIS OF CIRCUIT BOARDS
IPC TM-650 2.3.28.1 HALIDE CONTENT OF SOLDERING FLUXES & PASTES
IPC TM-650 2.3.25.2 BARE PRINTED BOARD CLEANLINESS

We monitor the ionic cleanliness of both printed circuit board fabrications and assemblies in accordance with IPC-TM-650 test methods 2.3.25 (Resistivity of Solvent Extract) for aggregate contaminants and 2.3.28 (Ionic Analysis of Circuits Boards, Ion Chromatography Method) for the following individual anion and cation contaminants:

CONTAMINANT ORIGINATION
FLUORIDE (F-) FLUX CHEMISTRIES
CHLORIDE (CL-) FLUX CHEMISTRIES
NITRITE (NO2-) FLUX CHEMISTRIES
SULFATE (SO4=) RINSING AND CLEANING PROCESSES
BROMIDE (BR-) FLUX CHEMISTRY HALIDES
NITRATE (NO3-) BARE BOARD FABRICATION PLATING PROCESS
PHOSPHATE (PO4=) FLUX CHEMISTRIES
AMMONIUM (NH4+) BARE BOARD FABRICATION PLATING PROCESS
LITHIUM (Li+) FLUX CHEMISTRIES
SODIUM (Na+) FLUX AND SOLDER MASK CHEMISTRIES
POTASSIUM (K+) DRY FILM SOLDER MASK CHEMISTRIES
MAGNESIUM (Mg+) SOLDER MASK FILLER CHEMISTRIES
CALCIUM (Ca+) SOLDER MASK FILLER CHEMISTRIES
ORGANIC ACIDS FLUX SYSTEM ACTIVATORS

The presence of anion, cation and weak organic acid contamination usually indicates a lack of process control in both the supply chain for raw materials and for process control parameters used in the production of the finished assembly. In most cases, ionic contamination will originate from printed circuit board fabrications and transfer upstream to the manufacturing process which will only contribute to the overall contamination of the finished product. Excessive amounts of ionic contamination on or around sensitive or high-frequency electronics circuitry can lead to an intermittent operation of the circuit, reduce the mean-time-between-failure (MTBF) of the circuit or results in complete circuit failure altogether through dendritic growth of the ions, making the importance of maintaining a laboratory for the continuous monitoring of ionic contamination on all levels of the manufacturing process clear.

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